Pulley for magnetic separation of solid wastes

ABSTRACT

An improvement on a conventional rotary magnetic pulley operating with a conventional belt for separating household rubbish into one fraction consisting mainly of magnetic and solid materials, and another fraction consisting mainly of useable fibers, by extending the ends of the conventional magnetic pulley with fluted non-magnetic materials, so that any under-the-belt accumulations will be passed out the sides of the pulley.

United States Patent [191 Danberg 1 Nov. 19, 1974 PULLEY FOR MAGNETIC SEPARATION OF SOLID WASTES [21] Appl. No.: 207,396

[52] US. Cl. 209/218, 198/41 [51] Int. Cl. B036 l/l8 [58] Field Of Search 198/41, 230; 226/190;

[56] References Cited UNITED STATES PATENTS 1,144,383 6/1915 Rothert 209/216 1,576,690 3/1926 U11rich.... 209/219 X 2,535,719 12/1950 Blind 209/219 2,844,251 7/1958 Leroy 209/218 X 2,939,580 6/1960 Carpenter .1 209/219 2,992,733 7/1961 Buus 209/219 3,038,590 6/1962 Arndt 198/230 3,055,229 9/1962 Mecham... 198/230 X 3,163,596 12/1964 Ferris 209/219 3,174,619 3/1965 Krane 198/230 Primary ExaminerRobert l-lalper Attorney, Agent, or Firm-Victor Danberg [5 7] ABSTRACT An improvement on a conventional rotary magnetic pulley operating with a conventional belt for separating household rubbish into one fraction consisting mainly of magnetic and solid materials, and another fraction consisting mainly of useable fibers, by extending the ends of the conventional magnetic pulley with fluted non-magnetic materials, so that any under-thebelt accumulations will be passed out the sides of the pulley.

4 Claims, 2 Drawing Figures PULLEY FOR MAGNETIC SEPARATION OF SOLID WASTES The object of the invention is to improve the structure of the magnetic pulley, so that the magnetic metal will not become attached to the bare magnetic pulley and thus ride underneath the conveyor belt.

The object of the invention is to prevent the conveyor belt from being cut, torn, or broken by metal accumulations, riding on the bare magnetic pulley underneath the conveyor belt.

The object of the invention is to prevent the forcible shifting of the conveyor belt from side to side by metal accumulations riding on the bare magnetic pulley.

The object of the invention is to prevent magnetic metals from riding on the bare magnetic pulley, by extending the sides of the magnetic pulley with nonmagnetic material.

The object of the invention is the construction of a fluted design in the non-magnetic side extensions of the magnetic pulley.

The object of the invention is to provide a magnetic pulley design, for use in the series of gradual magnetic belt separations, for the highly variable and adverse conditions, in grinding solid waste trash.

For the matter of convenience in this specification, the mention of magnetic belt will means a conveyor belt made of commercial material which passes over a magnetic pulley.

. FIG. I, is a sketch of a pulley with a conventional magnetic center section, with two fluted end extensions which are composed of non-magnetic material.

FIG. 11, is a sketch of a conventional conveyor belt supported in a U-shaped trough and rotating with a head magnetic pulley and a conventional tail pulley. The head magnetic pulley has a magnetic center face with two fluted end extensions composed of nonmagnetic material.

Referring to FIG. 1, for an illustration of the invention, number 1, is a magnetic pulley section. The two sides No. 2, and 3, are extended with non-magnetic material. The side extensions can be constructed in both a flat manner, or a fluted manner. A fluted construction would become an easy fall-out of both magnetic and nonmagnetic solids. The extension of each side could be from about one-fourth to about one-half the length of the magnetic pulley face.

Referring to FIG. ll, No. 4, is a magnetic pulley, with the sides constructed of non-magnetic material, such as aluminum. No. 5, is the conveyor belt. Number 6, is the bottom of the steel trough underneath belt 5. No. 7, and 8, represent the sides of the steel trough.

If Number 4, could be considered as only a full faced magnetic pulley, without any side extensions, ground waste trash containing iron metals being conveyed on belt 5, are held by magnet 4, until the belt 5, rotates over the magnetic pulley 4. The magnetic metal falls off below into a separate section. The nonmagnetic section of the trash is passed over for the next magnetic belt separation.

In these arrangements, some magnetic metals riding along the sides of the belt 5, could at times fall into the void spaces number 9, and 10. These metals can fall on the bare magnetic pulley under the belt and are held on the permanent magnetic pulley, until manually removed. These metals can also work their way on the trough 6, underneath the belt and then be pushed on the bare magnetic pulley. Conveyor belts have a norma] wear which elongates the belts. This slack in the belt can also be a factor to add metal on the bare magnetic pulley. The electro-magnetic pulley will also hold these metals until the power is shut-off.

The iron metals riding on the magnetic pulley, have a tendency to work their way to the point of the greatest magnetic force. These riding metals soon begin to buildup at this point. These accumulation of riding metals will begin to exert a pressure force on the conveyor belt. When such a condition occurs, the conveyor belt No. 5, has a tendency to shift to one side. 7-\s the belt is forced to shift to one side, the voids gaps at Nos. 9 or 10, become larger and more magnetic metal could fall and attach themselves on the bare magnetic pulley underneath the belt. Non-magnetic materials can also work their way under the belt. In this case, they will not attach themselves to the magnetic pulley, but will ride inside the belt. This action can also be harmful to the belt. Under these conditions, the belt will begin to show considerable wear and folding when forced against the metals sides 7, or 8, of the steel trough. If the build-up is large enough, it can break, tear, or cut the belt.

The invention of extending the magnetic pulley with non-magnetic material, is a solution to the problem. The resultant pulley has a section of magnetic force, and one or two sections of non-magnetic force on the ends of the magnetic pulley, as illustrated in FIG. 1.

When No. 4, is properly considered to be the altered magnetic pulley (as illustrated in FIG. 2) then, as ground trash containing magnetic metal passes over the altered magnet, iron materials are separated. When materials are carried by the sides of the belt No. 5, they fall on the ends of the altered magnetic pulley. The non-magnetic fluted extensions would have a tendency to drop the material out of the sides of the altered magnetic pulley and away from the pulley. Non-magnetic materials falling on the fluted sections of the magnetic pulley, will also be passed out of the sides of the pulley. In this manner, magnetic and non-magnetic materials could be prevented from working their way on the bare magnetic pulley and riding under the belts.

Test runs were made on a standard Eriez magnetic pulley, model 3C-81OF, manufactured by the Eriez Mfg., Company of Erie, Penn., having a l8 inch face with a 9 inch diameter and 2 inch diameter shafts, 7 inches and 10% inches long on each side. A 16 inch belt riding in a metal trough is used in this testing.

Since conveyor belts do not run perfectly true, allowances must be made between the edges of the belt and the sides of the trough. This small amount of clearance on both sides of the belt is necessary to prevent fraying and wear on the edges of the belt. The required clearances of the belt does increase the void gaps at 9 and 10.

TAB E I Numbcr Total Total Number of Number of nails Number of of I Amount Amount Nails held held by the nails Trials of of by Regular altered barc passed out FLOCK NAILS l8" magnet magnet the sides of (lbs) Barc altered magnet l 50 500 3 3 O 2 50 500 2 O 3 3 50 500 3 2 4 50 500 4 O 2 50 500 2 0 3 In five trial runs (table I) with the regular 18 inch In a test run, (table II), 50 lbs. of flock fiber was magnetic pulley, there were 2 to 4 nails riding on the bare magnetic pulley underneath the belt. In each successive trial run for the regular magnetic pulley, the nails of the previous test were removed from the magnet. This was done to prevent any chance of build-up on the magnetic pulley and possible shifting of conveyor belt. The total mixture of 50 lbs. flock and 500 nails were used for each trial run. If no nails were removed, than the total amount of nails after 5 trials, would have been 14 nails on the magnetic pulley. It is quite evident, if such accumulations were allowed to continue, the build-up of nails on the magnetic pulley would eventually cause the belt to start shifting. In that case, even more nails could fall through the enlarged voids at 9 or 10, and become attached to the magnetic pulley. This action would cause an even greater shifting or damage to conveyor belt.

With the invention of the altered magnetic pulley, the first trial run (table I), had 3 nails underneath the belt and the other 4 times had none, In the first trial, the three nails were embedded in the wood. The two outer wooden circles were removed and cut in a taper so that the wooden edges sloped away from the magnet. The other four trials did not have the problem of the embedded nails, since all nails passed out the sides of the magnet. All these trial runs had a mixture of 50 lbs. flock and 500 nails.

The non-magnetic extensions could work both as straight or built with a fluted design'for easy cleanout such as illustrated in (FIG. 1, Number 2). A fluted design would be the recommended extension.

Further testing of the extended magnetic pulley, showed a certain amount of nails were not removed by the altered magnetic pulley. The nails were not removed because they passed over the altered magnetic pulley on the non-magnetic section. Since there is no magnetic power in these sections, the nails were not separated out, but passed over. However, the object of the invention is to design a magnetic pulley that will fit into the repeated process of magnetic separations, as shown in the invention process of the solid waste trash grinding. The passing over of some magnetic metal is not detrimental for this type of separation.

mixed with 500 galvanized 1% roofing nails, in order to check the amount of nails not removed by the altered magnet. Tests were conducted to check the number of magnetic passes necessary to remove the nails. Series of successive runs were made to achieve almost complete magnetic nail separation. After each run, all the flock fiber mixture with the nails not magnetically removed, were again passed-over the magnet. All the nails removed by the magnet section in each run were not used in the next trial run. All the nails passed out the side of the magnet were not used in the next trial run. H

The second pass in table II, was composed of a mixture of flock and all the nails passed-over by the altered magnet. This mixture, composed of 50 lbs. of flock and I28 nails, was picked up and passed a second time over the same magnetic belt set-up. All the magnetically separated nails were removed and not used in the following mixture trial run. All the other trial runs, using 50 lbs. of flock, plus only the nails passed over by the non-magnetic section, were made in this manner. It is quite evident, that if no re-grouping were made of the mixture, the same nails would not be removed by any successive passes, on the alteredgnagnetic pulley.

Since the solid waste ground trash separation is done by gradual and successive steps, it is also necessary to regroup the trash mixture after each magnetic pass. This can easily be accomplished by placing each magnetic conveyor belt at right angles to the next belt. If all the magnetic conveyor belts are set at a right angle feed, it might be possible to use a magnetic pulley with only one side extended with non-magnetic material. It can also be done by dropping the solid waste ground trash into a hopper, which would make enough change in the mixture, for the necessary re-grouping. The regrouping in the test (table II), was accomplished by picking up the mixture and re-running. The speed of the magnetic belt in all test runs was constant.

Table II, shows that with such re-grouping of materials, successive magnetic belt separations can be accomplished. The magnetic metal content could be reduced to almost zero, with enough magnetic belt separations.

In the solid waste trash grinding and separation process, magnetic belt separations is a very important feature. It is necessary to make many magnetic belt separations in order to extract quantities of magnetic metals from the extreme variabilities of ground trash. It is also necessary to have the speed of each successive magnetic belt run a little faster than the last belt. Such increases of speed spreads and thins-out the trash load which will increase the efficiency of magnetic metal separation. Magnetic metals missed by the previous magnetic pulley could be separated on the following ones. Such missed magnetic metal could be due to the thickness of the trash layer, or mechanical attachment of iron to non-magnetic material, or passing over the nonmagnetic section of the magnetic pulley. Therefore, since the altered magnetic pulley does miss the separation of some magnetic metal, it is not a serious deficiency. The whole magnetic conveyor separation is dependent on a number of successive passes resulting in removing practically all of the magnetic metals.

The amount of metal that could be separated from the solid waste ground trash in one days production could be extremely large. The invention of the altered magnetic pulley could be invaluable in its ability to prevent, both iron metals from attaching themselves to the bare magnetic pulley, and non-magnetic materials riding under the belt. These accumulations could be very costly in time and money, if it were necessary to make many stops for manual clean-outs of the regular type magnetic pulleys. The self cleaning feature of the altered magnetic pulley can be useful for both magnetic and non-magnetic metals. The invention could prevent the breakage of many conveyor belts which could speed the metal separation of trash at a lower cost. The results of the test show that it is possible to operate the altered magnetic pulleys without much metal build-up. The invention would keep the belts running in good alignment without any excess wear or damage. The invention could be another step in the solution for disposal of solid waste trash.

1 claim:

1. A magnetic separator unit for separating magnetic material from a burden which must be scrambled and regrouped before passing on to the next of a series of magnetic separators, consisting of an endless conveyor belt passing over a head magnetic pulley and a tail pulley, said head magnetic pulley rotating about a shaft axially extending through said head magnetic pulley having a magnetic section and at least one end pulley extension, extending longitudinally and composed of nonmagnetic material, said end pulley extension being fluted, having at least one open tapering groove sloping in depth in the longitudinal direction, and said end pulley extension being about one-fourth to about one-half the face length of the magnetic section of the said head pulley.

2. A magnetic separator as defined in claim 1, wherein the said head magnetic pulley having a second end pulley extension being straight and flat and said second end pulley extension, extending longitudinally and composed of non-magnetic material and said second end pulley extension being about one-fourth to about one-half the face length of the said magnetic section of the said head magnetic pulley.

3. A magnetic separator as defined in claim 1 wherein the said scrambled and regrouped burden passing from one of the said series of magnetic separators to a successive magnetic separator in the said series of magnetic separators, said successive magnetic separator rotating a little faster than the preceding said magnetic separator.

4. A magnetic separator as defined in claim 3 wherein the next of the series of said magnetic separators are positioned about from said preceding magnetic separator. 

1. A magnetic separator unit for separating magnetic material from a burden which must be scrambled and regrouped before passing on to the next of a series of magnetic separators, consisting of an endless cOnveyor belt passing over a head magnetic pulley and a tail pulley, said head magnetic pulley rotating about a shaft axially extending through said head magnetic pulley having a magnetic section and at least one end pulley extension, extending longitudinally and composed of nonmagnetic material, said end pulley extension being fluted, having at least one open tapering groove sloping in depth in the longitudinal direction, and said end pulley extension being about one-fourth to about one-half the face length of the magnetic section of the said head pulley.
 2. A magnetic separator as defined in claim 1, wherein the said head magnetic pulley having a second end pulley extension being straight and flat and said second end pulley extension, extending longitudinally and composed of non-magnetic material and said second end pulley extension being about one-fourth to about one-half the face length of the said magnetic section of the said head magnetic pulley.
 3. A magnetic separator as defined in claim 1 wherein the said scrambled and regrouped burden passing from one of the said series of magnetic separators to a successive magnetic separator in the said series of magnetic separators, said successive magnetic separator rotating a little faster than the preceding said magnetic separator.
 4. A magnetic separator as defined in claim 3 wherein the next of the series of said magnetic separators are positioned about 90* from said preceding magnetic separator. 